Terrorism threat level in Britain raised to 'severe'

The change, which means an attack is now seen as highly likely, comes the day after a gunman in Vienna identified as a convicted jihadist killed four people in a rampage overnight. France has also suffered three attacks in recent weeks.

"This is a precautionary measure following the terrible instances that we've seen in France last week, and the events that we saw in Austria last night," Patel said in a televised statement.

She said the public should not be alarmed and that the change in threat level was not based on any specific threat.